​Poor sleep could increase risk of developing Alzheimer's – study

It's no secret that sleepless nights can cause dark circles and irritability, but researchers now believe it could also lead to Alzheimer's disease. The lack of shut-eye may cause memory-robbing proteins to build up in the brain, a new study says.

Researchers at the
University of California Berkeley have found that a deficit in
deep non-REM (Rapid Eye Movement) sleep is associated with a
higher risk of beta-amyloid protein build-up in the brain – the
type of protein believed to attack the brain's long-term memory
and trigger Alzheimer's diseas

Those higher levels of memory-robbing proteins then cause further
sleep disruption – resulting in a vicious cycle.

“The more beta-amyloid you
have in certain parts of your brain, the less deep sleep you get
and, consequently, the worse your memory,”researcher and UC Berkeley
neuroscience professor Matthew Walker said.

“Additionally, the less deep sleep you have, the less
effective you are at clearing out this bad protein. It’s a
vicious cycle.”

The study's lead author, Bryce Mander, said the study's data is
“very suggestive that there's a causal link” between
poor sleep and beta-amyloid protein.

"If we intervene to improve sleep, perhaps we can break that
causal chain,” he said.

The team's findings were published Monday in the journal Nature
Neuroscience.

The study consisted of
26 healthy adults aged 65 to 81, who showed no evidence of
dementia or other neurodegenerative, sleep, or psychiatric
disorders. They each received scans to measure the amount of
beta-amyloid in their brains.

They were then asked to memorize 120 pairs of words, and were
tested on how well they remembered a portion of them.

The participants then slept for eight hours, during which their
brain waves were measured. The next morning, their brains were
scanned as they recalled the remaining word pairs.

Researchers tracked activity in the hippocampus – the area where
memories are temporarily stored before moving to the prefrontal
cortex.

“The
more you remember following a good night of sleep, the less you
depend on the hippocampus and the more you use the cortex,”Walker said.“It’s the equivalent of
retrieving files from the safe storage site of your computer’s
hard drive, rather than the temporary storage of a USB
stick.”

The results showed that those with the highest levels of
beta-amyloid in the medial frontal cortex had the poorest quality
of sleep and performed worst on the memory test the following
morning. Some forgot more than half the information they had
learned the day before.

But despite the researchers' conclusion that the bad protein and
poor sleep lead to a “vicious cycle,” it remains unclear which
one begins the cycle. This will be the foundation of further
research, as scientists set out to track a new set of older
adults over the next five years.

"This is a new pathway linking Alzheimer's disease to memory
loss, and it's an important one because we can do something about
it," Mander said.

Alzheimer's is the most common form of dementia, accounting for
60 percent to 80 percent of cases of the condition. Nearly 44
million people are currently living with the disease, according
to Alzheimer's Disease International.

As the Baby Boomer generation continues to age, Alzheimer's is
expected to become one of the world's fastest-growing and most
debilitating public health concerns.